According to one of the responses to the YouTube clip, Kevin Pollak had done a more extended imitation of Boitano earlier in that routine, and worked it into the Shatner sketch to end the routine.

I've seen stand-up comedians do that more and more lately -- put part of an earlier bit into the last bit as a sort of exclamation point on the whole routine -- and it annoys me. I guess it's supposed to be clever, but to me it's just an affectation. It's a kind of a cheap laugh, since the comedian already knows that the audience found it funny the first time. Sorry, but I don't find it as funny the second time it pops up in the routine; it lets me down. "Oh, that old thing again," I find myself thinking. Why can't they close with something new that will make me laugh, rather than something that makes me work to remember why it was supposed to be funny several minutes ago?